scalar diffusion. Among other examples, Stein equation implies that the mean of Hermite polynomials is zero. The GMM approach … contribution of the paper. The second reason for using GMM is that our tests are also valid for time series. In this case, we adopt …?espérance de chaque polynôme de Hermite est nulle. L?approche GMM est utile pour deux raisons. Elle nous permet de tenir compte du …